This invention is an improvement of a machine, of the type shown in U.S. Pat. Nos. 3,975,932 and 4,020,660, which operates on a shoe assembly comprised of an upper mounted on a last and an insole located on the last bottom with the margin of the upper secured to the last bottom, by roughing the upper margin a desired distance inwardly of the margin periphery including a non-rectilinear portion of the margin periphery. The prior machine includes a support for supporting the shoe assembly; a sensing member, located rearwardly of the support, adapted to engage a non-rectilinear side of the shoe assembly corresponding to the non-rectilinear portion of the margin periphery; a roughing tool, having an operating portion located forwardly of the sensing member in forward-rearward alignment with the sensing member, adapted to perform the roughing operation; means for so moving the support as to move the shoe assembly side past the sensing member and as to move the corresponding portion of the upper margin past the roughing tool; and means for causing the sensing member and the roughing tool to so move forwardly and rearwardly in unison during the support movement as to enable the sensing member to be in engagement with the workpiece side and as to enable the roughing tool to perform the roughing operation along the upper margin.
As explained in U.S. Pat. No. 3,975,932, when roughing curved concave portions of the sides of the shoe assembly with the prior machine of this patent, the roughing tool tends to rough the upper margin too close to the margin periphery where the upper side joins the upper margin which is undesirable as the roughed upper would then be visible in a finished shoe. In order to overcome this deficiency, in the machine of U.S. Pat. No. 3,975,932 the roughing tool is so mounted as to be displaceable along its line of forward-rearward alignment with the sensing member so that it can be moved a relatively great distance forwardly of the sensing member when the curved concave side portions of the upper margin are moved past the roughing tool. However, the amount that the roughing tool should be displaced along the line of forward-rearward alignment in the arrangement of U.S. Pat. No. 3,975,932 is proportional to the angle that the tangent of the curved portion of the margin makes with the rectilinear path of movement of the shoe assembly in its movement past the sensing member and the roughing tool, and this angle varies with different segments of the curved side of a particular shoe assembly, is different for the inside and outside side portions of a particular shoe assembly, and is different for different styles and sizes of shoe assemblies.